This term refers to the absorption of male Y cells into the female body. It is demonstrated to occur by pregnancy with a male child.

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0045592

Findings also suggest that women also absorb Y cells and keep them in their bodies directly through contact with sperm. I.E. women with no history of abortions or male children have Y cells in their bodies of foreign origin. A female homing pigeon that is mated by a wild male will never again produce pure homing pigeon offspring. Similar phenomenon exist in animal husbandry across multiple species.

I theorize that the patriarchal oppression that these modern women supposedly experience is sourced from having an over abundance of male cells in their brain. They literally can't handle it. These cells also carry the individual genetics of the male sources, which represents their character and mind. Hence if she is blowing tons of guys with different ideologies, her brain is going to be full conflicting thoughts.

I believe this phenomenon to be the impetus behind the virgin bride tradition. I've seen many ways to explain it and I'm happy to hear other perspectives about it.